References which are cited in the present disclosure are not necessarily prior art and therefore their citation does not constitute an admission that such references are prior art in any jurisdiction.
The herb Brachystemma calycinum D. Don (B. calycinum) is a plant indigenous to southern-western China, the Himalayas and its habitat range extends as far south as South-East Asia. In China, the herb is known as “duanfan hua”. The herb is relatively unknown to the scientific community and very little of it outside of the plant systematics and taxonomic literature has been published.
In 2001, a paper describing four minor cyclic peptides isolated from ethanolic extracts from this plant was published (Cheng et al). In 2002, Cheng et al isolated five nitrogen-containing compounds from an ethanol extract of the herb. Five novel alkaloids were also isolated from the roots of the herb by Cheng et al.
It is an object of the present invention to teach a method of preparing a useful extract of this herb.